Many health decisions are base on experimentation and statistical analysis of results. Extensive background in statistics, numerical analysis and numerical software will be applied in building program tools for evaluation and tabling of probability functions. The tools will evaluate and graph discrete and continuous density functions, evaluate, graph, table, and invert discrete and continuous distribution functions, and evaluate and table probabilities for nonparametric tests. The availability of these tools will allow statistical and biostatistical workers quick access to accurate and consistent probability information heretofore available only in part and in tabular form. Users not familiar with tabular probability presentations will find probabilities needed for examining experimental results and hypotheses easily accessible in a simple framework. Emphasis will be on accuracy and usage ease. Phase I will address a small set of functions and tests and lay groundwork for Phase II efforts on a complete (for statistical needs) set. The menu driven programs will operate on micro- computers under MS-DOS. During Phase II they will be transported for operation under OS/2 and on the Macintosh II computer. This will allow extension of accuracy and user protection. Full IEEE binary floating point standard support will then be available.